Automatic telephone-repeater.



PATENTED MAR. '7, 1905.

E. PARSONS. AUTOMATIC TELEPHONE REPBATER.

APPLICATION FILED FBB.16, 1903.

l/V VE N TOR I/VITNESSES no. verglas.

Patented Ill/[arch *7, 1905.

FF C tu EMORY PARSONS, OF CHICAGO, ILLINOIS.

UTOWlATlC TELEPHONEHQEWEATEH.

SPECIFICATION forming part of Letters Patent N0. 784,175, dated lvarch 7', 1905.

Application tiled February 16, 1903. Serial No. 143,478.

To /tZZ '1071/0711, it 71mg/ con/cern.-

Be it known that I, EMonY PARSONS, a citizen oi' the United States, residing' at Chicago, in the county ot Cook and State oi illinois, have invented new and use'lul improvements in Automatic Telephone-ltepeaters, ol which the following' is a speciiication, reference being' had to the accompanying' drawings, forming' a part thereof.

The purpose ot' this invention is to provide an'improved device for rel'ieatiug' sound from a receiver to a transmitter interposed on a telephone-line for the purpose of increasing' the distance to which a message may be transmitted by telephone.

It consists in the Jfeatures of construction shown in the drawings and set out in the claims.

In the drawings, Figure l is an axial section of my improved telephone-repeater. Fig'. Q is a section at the line 2 2 on Fig'. l. Fig'. 3 is a diagrammatic view showing' the circuits between two remote instruments embodying my invention. p

h/Iy improved telephone-repeater comprises two receivers placed upon opposite sides 0i' a duplicate transmitterthat is to say, a transmitter having' a diaphrag'm on each side adapted to receive vibrations from the duplicate receivers, respectively, and g'ive corresponding' pulsation to the line-current with the aid ot' an induction-coil. lhis intermediate transmittercomprises thetwodiaphragmel l, which are spaced by the short cylinder L), made ol insulating' material, ag'ainst the ends oi which the diaphragme are lodged. Each diaphragm has at the center a block 3 ol electrically-conductive material, the blocks facingl each other and being' telescopcd into the opposite ends ol the short tube 4, which is oi insulating' material, the space in the cylinder t between the two blocks 8 being' occupied by granulated carbon 5. The diaphrag'ms are held ag'ainst the ends of the spacing-cylinder 2 by shoulders 6 6 of the opposite annular frames or cases 77, which arethemselves bound together' by screws 8. These cases inclose the receivers, the diaphragms 9 9 of such receivers being' lodg'ed therein spaced away from the diaphragms at 1 l of the transmitter by spacing'- ring's 10 l() of insulating' material,the receivero may represent the line-wire on which the pulsation due to a transmitter elsewhere on the line is coming' in. This line-wire is divided sending' two branches u/ and fr? to the electromag'net-coils oi" the two receivers, and from them corresponding' branches b and o extend and are joined in the return-.wire

From this construction it will be uiulcrstood that there will result synchronous vibration of the two diaphragms of the duplex transmitter, causing' corresponding' pulsations in the local circuit, which comprises the grannlated carbon between the diaphrag'ms, the local battery, and the primary wire of the induction-coil, so that in the secondary wire ot the latter there will arise a correspornlinglypulsating' induced current, by which the sound will be transmitted b v means olE the line to a distant receiver. In order to transmit and repeat automatically in both directions over the line, l employ these repeaters in pairs, connecting' the several elements in the manner shown in the diagram Fig. 3, b v reference to which it will be understood that in addition tO branching" the wires f/ and to lead to the electronlag'net-coils ol the receivers oll that instrument they are also provided with branches il and "i to the secornlary wire ol' the induction-coil ol the other instruments AIn order that the maxinnnn el'lect oll the incoming' current may befprod uced on the transmitter for causing' pulsation in the local circuit which includes the primary wire ol the induction-coil, the resistance in the branches ot' the circuit which include the two receivers which influence such transmitter should bc `preferably less than that ol the parallel branch comprising' the wires a .//i ot' the sec` lOO ondary coil 16 of the other instrument, since obviously it' this last mentioned parallel branch constituted a relatively very short circuit the eiect desired upon the transmitter from the two receivers would be materially reduced.

I claiml. A telephone-repeater comprising a transmitter having a plurality of diaphragms; a rnedium interposed between the diaphragms, exposed to their vibrations; a local circuit comprising such medium and the primary wire of an induction-coil; a like plurality of telephonereceivers having their diaphragms facing the transmitter-diaphragms respectively; an incoming-line circuit which is branched to include in parallel the electromagnet-coils of the several receivers, the secondary wire of the induction-coil being in the outgoing-line circuit.

2. Repeating devices for a telephone-circuit comprising a pair of instruments, each comprising a transmitter having a plurality of diaphragms; a medium interposed between the diaphragms and exposed to their vibrations; a local circuit comprising such medium and the primary wire of an induction-coil; a like plurality of telephone-receivers having their diaphragms facing the transmitter-diaphragms respectively; an incoming-line circuit Which is branched to include in parallel the coils or' the electromagnets of the several receivers, the secondary wire or' the induction-coil of each instrument being a branch circuit from the incoming-line circuit of the other instrument, and in parallel with the branches to the electromagnet-coils of the same, the resistance of said secondary wire being greater than the resistance of the electromagnet-coils.

3. A telephone-repeater comprising a transmitter having a plurality of diaphragms; a medium interposed between them and exposed to their vibration; a local circuit comprising such medium and the primary wire of the induction-coil; a like plurality of telephone-rcceivers having their diaphragm-infiuencing magnets in position to iniiuence the transl mitter-diaphragms respectively; an incomingline circuit which is branched to include in parallel the coils of such magnets respectively, the secondary wire of the induction-coil constituting the outgoing-line circuit.

4. A telephone-repeater comprising a shell or casing, a plurality of diaphragms and a medium interposed between them exposed to their vibration or inclosed within the shell or casing and constituting a transmitter, and a like plurality of telephone-receivers contained within the same casing having their diaphragms facing the transmitter-diaphragms respectively at a short interval, forming an inclosed air-chamber between the corresponding diaphragms of the transmitter and receivers respectively; a local circuit comprising the medium interposed between the transmitter-diaphragms and the primary wire oi an induction-coil; an incoming-line circuit which is branched to include in parallel the electromagnet-coils o1 the several receivers, the secondary wire of the induction-coil being in the outgoing-line circuit.

Atelelihone-repeatercomprisinga transmitter having a plurality of diaphragms; a medium interposed between the diaphragms exposed to their vibrations; a local circuit comprising such medium and the primary wi re oi an induction-coil; a like plurality ol: telephone-receivers having their diaphragme facing the transmitter-diaphragms resiiectively at a short interval ati'ording air-space between the facing diaphragms respectively` and a shell which encompasses and incloses such airspace; an incoming -line circuit which is branched to include in parallel the electromagnet-coils of the several receivers; and the secondary wire oi theinduction-coil, which is located in the outgoing-line circuit.

In testimony whereof 1 have hereunto set my hand, in the presence of two witnesses, at Chicago, Illinois, this 6th day ot' February, 1903.

EMORY PARSONS.

YIn presence cfm l). McLAUGi-ILIN, J. J. HOWARD. 

